Boxed-in slot antenna with space-saving configuration

Abstract

The boxed-in slot antenna is provided with a conductive box, functioning as a waveguide, which is configured substantially parallel to the ground plane in which the slot is formed, thereby providing significant space savings relative to prior art designs wherein the box is positioned perpendicular to the conductive ground plane. The inventive antenna can be easily constructed using printed circuit board technology, by forming the ground plane as a coating on one side of a printed circuit board substrate, forming the main conductive plane of the conductive box structure on the other side of the printed circuit board, and interconnecting the two using plated through holes (that is, vias). The folded structure of the conductive box of the present invention makes it particularly suited for space-critical applications, such as may be found in laptop computers and other portable and handheld electronic devices, which it is desired to interconnect with a wireless local area network (wireless LAN).

What is claimed is:  
     
       1. In combination: 
       (a) a portable electronic device having at least one conductive portion; and  
       (b) a boxed-in slot antenna comprising:  
       (b-1) a conductive ground plane having first and second sides, said conductive ground plane having a slot formed therein, said slot being configured and dimensioned for predetermined radiation performance with radiation having a waveguide wavelength λ g , said conductive ground plane being electrically interconnected with said at least one conductive portion of said portable electronic device; and  
       (b-2) a conductive box structure which is conductively secured to said conductive ground plane and which is configured to function as a waveguide causing said slot antenna to radiate from only a single one of said first and second sides of said conductive ground plane, said conductive box structure having a main conductive plane, a substantial portion of which is substantially parallel to said conductive ground plane and spaced a distance d therefrom, said distance d being substantially less than one quarter of said waveguide wavelength λ g , whereby a folded, space-saving configuration for said conductive box structure is achieved.  
     
     
       2. The combination of  claim 1 , wherein said conductive ground plane of said boxed-in slot antenna is formed integrally with said at least one conductive portion of said portable electronic device.